Consider a body of mass $m$ kg on a smooth inclined plane inclined at an angle of $\theta$ to the horizontal. Let $R$ be the magnitude of the normal reaction force acting on the body.
If I resolve forces vertically, I get $Rcos\theta=mg$
And if I resolve perpendicular to the plane, I get $R=mgcos\theta$
Clearly this is not possible. What am I doing wrong exactly?